Fluid pump



Oct. 17, 1-939. E. R. BARRETT 2 FLUID PUMP Filed June 28, 1937 2 Sheets-Sheet 1 INVENTOR fin 4rd Rfiarraif. 1'

A TTORNE 1 s;

- Oct. 17, 1 939. E. BARR E TT- FLUID PUMP Filed June 28, 1937 2 Sheets-Sheet 2 INVENTOR liar-rail.

fin era )2 A. TTORNE ya.

Patented Oct. 17, 1939 Edward R. Barrett, Detroit, Micln, assignor to Gar Wood Industries, 1110., Detroit, Mich, a

corporation of Michigan Application June 28,

6 Claims.

1 V ing fluid under pressure to various hydraulic operating devices.

It is aprimary object of the present invention to provide a pump which will operate relatively efliciently at low speeds and maintain substan- 9. tial uniformity of operation throughout an extremely wide range of speed and load conditions.

Still another object of the present invention is to-provide a pump construction which is easily and conveniently attached to the power take-ofi 1. of a vehicle such, for example, as a tractor and may be mounted in such a manner that the power take-off may conveniently be used for other purposes.

It is a still further object of the present invention to provide a pump construction which is substantially symmetrically arranged in order that the position of the pump may be reversed thereby making the pump adaptable to either clock-wise or counterclockwise drive.

An important feature of the present invention residesin the novel and improved sealing means utilized in connection with the gears of the pump inorder to provide a tight and effective seal for the axial ends of the gears which seals are effective to compensate for wear andtake up lost motion in'the mechanism.

Still further the'present invention contem plates'the provision of a novel and improved type of seal for tightly sealing 'the axial ends of the 'pump gears which seal utilizes the pressure of "fluid supplied by. the pump for maintaining the I seals tight, consequently, providing a structure in which the tightness of the seals is controlled in accordance with the discharge pressure existing onthe discharge side ofthe pump thus bringing the seals to maximum efliciency during the times when the discharge load is greatest.

Many other and further objects, advantages, and features of the present invention will become apparentfrom the following specification when considered in connection with the accompanying drawingsforming a part thereof. a

In the drawings: Figure 1' is a transverse sectional view taken through a; pump illustrating in detail the mounting of the various parts therein.

Fig. 2 is an enlarged fragmentary sectional view of'the improved seal construction. 3 Fig. 3 is an elevational view of one of the im- 1937, Serial No. 150,660

proved sealing plates utilized for closing the axial ends of the pump housing. Fig. 4 is a vertical sectional view taken substantially on the line 4-4 of Fig. 1 illustrating in detail the interior arrangement of the parts.

Fig. 5 is a front elevational view of. the pump housing structure illustrating the exterior configuration thereof.

With more particular reference to the drawings, it will be readily appreciated that the structure disclosed therein illustrates an extremely specific embodiment of the present invention and merely discloses one form thereof which has been found to be a particularly satisfactory applica-- tion of the improvements of the present invention. However, it will be readily apparent to those skilled in the art that the broad inventive principles disclosed in the application will flnd broad and practical utility in many and various installations different from that shown and disclosed in the drawings.

The pump housing as a whole comprises a casting ill which is provided with a flange ll by which it may be bolted to a valve structure or fluid supply reservoir in sealing relation there-. with in order that the intake and exhaust ports may conveniently communicate with suitable inlet and discharge openings in-the structure to which the device is secured. ,The exterior surface of the housing is preferably provided with a plurality of cooling ribs -l2 which substantially increase the exposed surface of the housing proper and aid in maintaining the device properly cooled at all times. The housing It has integrally formed therewith interiorly thereof wall structures I3 which are spaced from the outer wall of the housing Ill and serve to provide between them and the outer walls, intake ports it through which fluid to be pumped may be drawn inwardly through the pump mechanism hereinafter described in detail.

The wall structures iii are preformed to provide a discharge port I5, the mouth of which lies in substantially the same plane as the face of the flanges il in order that the discharge port may be sealed in communication with a suitable outlet port at the time the housing structure'as a whole is bolted imposition. The housing structures I! each have an interior configuration adapted to receive and closely house pump gears l1 and la which are mounted on shafts l9 and 20, respectively, and which gears are arranged in intermeshing engagement so that as the shafts l9 and are rotated, fluid will be drawn through the ports M and discharged through the port i5 as is conventional in gear pumps of this generic type.

-The gears Ill and I8 are keyed to their respecplurality of registering apertures adapted to re-- ceive' bolts 39 which may be drawn up to loci; the parts in assembled relation. The castings 28 and 2t each carry a series of ball bearings, 36 for the shaft 59 and a second set of ball bearings, 32 for the shaft 2d. 6

While it is immaterial which of the shafts i9 and 2B is driven, in the construction shown, the drive is adapted to be transmitted to the apparatus through the shaft 89 which, as is illustrated, is considerably longer than the shaft 2@ and has the ends thereof splihed to provide suitable driving connections. The ends of the shaft 69 pass outwardly through the castings 28 and 2a. In order to preclude the escape of oil at this point seals may be provided comprising metallic rings 35 sealed to the shaft is by means of springs 33 into contact with plates 39 which surround the shaft is and, are bolted to the casting by means of screws til. From this construction, it will be seen that access may conveniently be had to the splined ends of the shaft 59 yet at the same time sealing this shaft with respect not only to the housing it but with respect to the castings 2t and 29.

It will be noted that the shaft 253 is considerably shorter than the shaft is and that the axial ends of this shaft are completely enclosed within the castings wand 29 thus obviating the necessity-of any sealing means for this shaft what soever. It will be noted that each of the ball bearing assemblies, generally designated as M and 32, include an inner raceway 5B which is retained in predetermined axial position on the shaft with which it is associated, by means of a screw collar 5!! which may be threadably received upon the shaft and locked against rotation by means of a conventional lock washer 52. These raceway members 50..serve to support in predetermined axial position upon the shafts l9 and 20, sealing rings 55, the purpose and function of which will hereinafter become more clear. It has been found particularly desirable to provide the shafts l9 and It of enlarged diameter in their axial central portions in order to provide shoulders against which the sealing rings 55 may be clamped by means of the raceway elements thus positively locking these sealing rings in predetermined position upon the shafts with which they are associated.

Each of the sealing rings 55 is provided with an annular groove or channel 56 in the axial face thereof which is presented toward the gears carried by the shafts l9 and'2il. Likewise, the gears if and 18 each have a continuous channel or groove 5i in the axial faces thereof which groove is of substantially the same general size and shape as the grooves in the sealing rings 55. The plates 25 have apertures 60 and 55 therein adapted to receive the enlarged central portions of the shafts l9 and 2t, respectively, and the interior surface of these plates in these apertures is recessed to provide relatively deep channels 63 opening toward the axis of the shafts which they surround. These channels 68 are so formed as to provide a pair of relatively thin slightly flexible walls,-

one of these walls being adjacent one of the gears and the other of the walls being adjacent one of the sealingrings 55. A plurality of apertures 66 may be provided through these walls to establish communication between the channels 63 and the channels 56 and 571'. The sealing plates are each drilled to provide a bore W which communicates with a pair of branch bores H which branch bores each communicate with one of the channels 63. It will be noted that the bore H3 is located on the discharge or high pressure side of the pump.

It will be apparent that when the shaft iii-is driven, it will serve to effect rotation of the intermeshing gears if audit thus forcing fluid through the pump housing and discharging the same through the port l5. vA. small portion of the fluid will pass through the bore H3 in each of the plates 25 and thence through the branch bores ii into the channels 63. As has been explained above, the fluid filling the channels 83 may pass through the ports 66 into both the channels 5'5 and El formed respectively in the sealing rings .55 and the axial faces of the gears ll azd it. After the pump has been running a short time; it will be apparent that the oil being pumped by the apparatus will substantially fill the channels 53 in each of the plates as well as the channels 55 in each of the sealing rings and the channels 57 in the axial faces of each of the gears. It will be apparent that the surface area to which the fluid is exposed on the interior walls of the channels 63 is substantially greater than the area to which this fluid is exposed on the exterior walls of these channels. Consequently, the fluid pressure will cause the walls of the channel 63 to tend to move away from each other thus forcing these walls into tight sealing engagement with the sealing rings 55 and axial faces of the gears, effecting 'a tight seal for the axial ends of the gears at all times.

Due to the fact that these walls of the channel 63 are relatively thin and slightly flexible, the existence of this diiferential fluid pressure will maintain this tight sealing engagement at all times during the operation of the pump and will serve to compensate for wear as the same takes place.

This sealing engagement. is regarded as a particularly important feature of the present invention and is of particular significance in connection with pumps of the generic type disclosed herein because it will be noted that it is inherent that the forces serving to seal the axial ends of the pump will be greatest when the pump is operating under the most severe loads, consequently, greatly increasing the efllciency of the apparatus during the time when such efliciency is most essential.

The converse is likewise true and it may be readily appreciated that during phases of operation in which the discharge pressure is relatively low, considerably less pressure will be effective to obtain the sealing effect thus eliminating wear on the parts during the times when maximum operating eficiency is not necessary.

It will further be appreciated from the disclosure described above that the pump construction as a whole is generally symmetrical in configuration and is of relatively short axial length. It will be seen that both ends of the shaft it are provided with splines to facilitate the connection to of driving or driven members thereto and, consequently, the pump may be conveniently mounted in cooperation with the power take-off of a truck, tractor, or other vehicle and conveniently used for the operation of fluid pressure responsive devices. It will be seen that due to the fact that both ends of the shaft l9 are splined, the pump may be operated with equal efficiency by means of a power take-off which rotates in either clock-wise or counterclock-wise direction and that the device shown may be attached in operative relation to the power take-off utilizing either end of the shaft IQ for the purposes of such connection. Further, it will be appreciated that once the device has been mounted in position, one end of the shaft 19 will be free and other power operated device may be connected thereto if desired.

- From the foregoing, it will be appreciated that the apparatus will find broad practical utility for use in connection with the operation of various hydraulic actuating mechanisms commonly associated with trucks and tractors and is of particular practical importance in this field because I of the extremely high efficiency obtained by the device throughout an extremely wide. range of operation conditions. As is well understood in connection with devices of this general character, the power take-off mechanisms by which pumps of this general character are usually driven, rotates at a speed directly proportional to the speed of the motor. motor of the tractor or truck is primarily utilized for propelling the same, the discharge of oil from the pump cannot always be regulated by regulating the speed of the motor and, consequently, it is necessary to provide a pump construction in which adequate discharge pressures may be maintained throughout an extremely wide range of engine operation.

While but one specific embodiment of the in- -of said wall structure around said aperture being formed to provide a channel therein facing to- .ward said shaft, and means for supplying fluid pressure to said channel to urge said wall structure into sealing engagement with the adjacent axial faces of said sealingring and gear.

2. In a pump structure, a shaft, a pump gear locked thereon, a wall structure adapted to engage the axial face of said gear and having an aperture therein to receive said shaft, a sealing ring locked on said shaft and adapted to engage the outboard side of said wall structure, the edge of said wall structure around said aperture being formed to provide a channel therein facing toward said shaft, and means for urging the sidewalls of said channel away from each other Due to the fact that the to force the same into sealing engagement with the adjacent axial faces of said gear and sealing I ring. I

3. In a pump structure, a shaft, a pump gear locked thereon, a wall structure adapted to engage the axial face of said gear and having an aperture therein to receive said shaft, a sealing ring locked on said shaft and adapted to engage the outboard side of said wall structure, the edge of said wall structure around said aperture being formed to provide a channel therein facing toward said shaft, and means establishing communication between the discharge side of said pump and the interior of said channel whereby to expand the side walls of said channel into sealing engagement with the adjacent axial faces of said sealing ring and gear whereby the sealing force will be substantially proportional to the discharge pressure of said pump.

4. In a pump construction, a shaft, a pump gear locked thereon, a wall structure adapted to engage the axial face of said gear and having an aperture therein to receive said shaft, a sealing ring locked on said shaft and adapted to engagethe outboard side of said wall structure, the edge of said wall structure around said aperture being formed to provide a channel therein facing toward said shaft, a duct having one end opening insaid plate on the discharge side of said pump and the other end opening into said channel whereby fluid pressure from the discharge side of said pump may expand the walls of'said channel into sealing engagement with the adjacent axial faces of said gear and sealing ring.

5. In a pump construction, a shaft, a gear locked thereon, a plate having its inboard face adapted to engage the axial face of said gear and having an aperture therein adapted to receive 1 said shaft, a sealing ring locked on said shaft and adapted to engage the outboard surface of said plate, the edge .of said plate adjacent saidaperture being bifurcated to provide a channel therein facing toward the axis of rotation of said shaft, and means for supplying fluid pressure to said channel to expand the walls thereof into sealing engagement with the adjacent axial faces of said sealing ring'and gear.

6. In a gear pump construction, a shaft, a gear locked thereon, a 'plate having the inner surface thereof adapted to engage the axial face of said gear and having an aperture therein adapted to receive said shaft, a sealing ring locked to said shaft and having one axial face thereof adapted to engage the outer surface of said plate, said plate having the marginal edge thereof adjacent said aperture bifurcated to provide relatively flexible wall structures each having the outer surface thereof engaging an axial face of said gear and sealing ring, thus forming a channel therebetween facing toward the axis of rotation of said shaft, the axial faces of said gear and sealing ring adjacent said plate being provided with annularly extending channels therein, said wall structures having ports establishing communication between the channel in said plate and said last mentioned channels, and means for supplying fluid under pressure to all of said channels.

' EDWARD R. BARRETT. 

